As I recall from recent History Channel investigative documentary, DNA analysis showed that those chunks of skull in Moscow weren't his (via comparison to his relatives), or even of a male. His remains are probably in Brazil or Paraguay.
You might find interesting the Soviet history of his remains post WW2.
They hunted down his dentist/dental assistant, mapped his jaw, and confirmed who they had. Stalin did not want it known that they had a dental confirm, as using the “he escaped to Paraguay” meme was more helpful to his political goals.
His remains, and those of Eva, were buried at a Soviet encampment (military intelligence building) until they were again dug up decades later.
There is a lot of this out there and you can chose to believe anyone you want. I believe the bunker maintenance team (who were there until the end) and the more documented accounts of his last day and of the hunt for his corpse.